auto electrician or merc specialist??

auto electrician or merc specialist??

Author
Discussion

karatemaserati

Original Poster:

160 posts

143 months

Monday 24th January 2022
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to look at my merc that has an electrical fault that i think is comming from the front SAM

jfdi

1,140 posts

182 months

Monday 24th January 2022
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What's the fault?
The SAMs are fairly simple items that take the canbus signal and trigger the appropriate relay, any issues are more likely the be with the relay or associated fuse or their connection into the SAM.
When the wipers on my GL wouldn't work a lot of head scratching and guess work narrowed it down to the relay in the front SAM not having good contact with the socket. Removed relay thickened the legs on the relay by applying a thin layer of solder to each leg plugged it back in and it's all been working fine for 4 years now.

ingenieur

4,221 posts

188 months

Monday 24th January 2022
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karatemaserati said:
to look at my merc that has an electrical fault that i think is comming from the front SAM
You just want a decent mechanic for that job. Auto electricians don't really exist the same way they used to. There was a time when electronics on a vehicle were a bit of a new idea and if something went wrong you'd get a specialist to look at it. These days the computer diagnostics tells you everything to check as a mechanic. You follow the suggested steps on the screen and you'll find the problem sooner or later.

karatemaserati

Original Poster:

160 posts

143 months

Tuesday 25th January 2022
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intermitant not starting and would only go with a jump from a running engine not a jump pack.

had a specialist look at it told me it was water ingress to the front sam, they cleaned the contacts and conections and it worked... untill the next time it rained... but it wasnt directly the next time it rained, it was the next time it rained and then I DROVE stopped and tried to start... I unblocked a drain in the wheel arch under the SAM and the problem didnt come back for 6 months... so i had thought it was the blocked drain causing water to pool underneath the sam and sloshing around when i drove.

now the the exact Same symptoms have returned but it wont go with a jump so maybe its different.

ingenieur

4,221 posts

188 months

Tuesday 25th January 2022
quotequote all
karatemaserati said:
intermitant not starting and would only go with a jump from a running engine not a jump pack.

had a specialist look at it told me it was water ingress to the front sam, they cleaned the contacts and conections and it worked... untill the next time it rained... but it wasnt directly the next time it rained, it was the next time it rained and then I DROVE stopped and tried to start... I unblocked a drain in the wheel arch under the SAM and the problem didnt come back for 6 months... so i had thought it was the blocked drain causing water to pool underneath the sam and sloshing around when i drove.

now the the exact Same symptoms have returned but it wont go with a jump so maybe its different.
When it fails to start is it the starter motor not turning or does the starter motor turn but the engine won't fire?

karatemaserati

Original Poster:

160 posts

143 months

Wednesday 26th January 2022
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wont turn, you dont here the fuel pump pick up either